Has Kim Yeo Jin Been Blacklisted?

Many wonder about the “Entertainer Blacklist” of broadcasting companies. Actress Kim Yeo Jin recently implied on social media that her original casting by two major broadcasting companies became void due to her support for the opposing political party that ran against the current major party for the recent presidential election.
The translation of her tweets is as follows:

I’d expected this. It makes me annoyed.

For those in power in broadcasting industry, why don’t you share your blacklist of people who supported Moon Jae In?

Do I have to listen to writers and production directors saying “sorry, but we were told you can’t” after everything is set? This is nasty.

Can someone tell me what the problem is?

It’s been also said that Kim Je Dong, comedian Kim Mi Hwa, and singer Yoon Do Hyun had to resign for criticizing the major party in the past.
Do you think Entertainer Blacklist really exists?